1. Division of Nephrology Department of Internal Medicine University Medical Center Groningen University of Groningen Groningen The Netherlands
2. Department of Pathology and Medical Biology University Medical Center Groningen University of Groningen Groningen The Netherlands
3. Department of Epidemiology University Medical Center Groningen University of Groningen Groningen The Netherlands
4. Department of Laboratory Medicine University Medical Center Groningen University of Groningen Groningen The Netherlands
5. Department of Biomedical Research University of Bern Bern Switzerland